This invention relates to let-off apparatus for positioning a support for receiving a web roll, for cushioning the impact of the web roll when being placed upon the let-off, and thereafter for carrying the web roll for rotation during unwinding.
Several kinds of let-offs are provided for use in unwinding the web from a web roll including center wound and surface wound let-offs as well as belt let-offs illustrated in U.S. Pat. No. 5,209,418. The apparatus of the invention may be used to greatest advantage upon the belt let-off but may be useful in connection with other let-offs as well.
A major problem in connection with the placing of a web roll upon a belt let-off results from the force with which extremely large web rolls, which may weigh on the order of about 6,000 pounds, are rolled into a cradle formed by the belt provided for supporting and rotating the web roll during unwinding. The impact exerted by a full web roll being placed upon a belt let-off may cause damage to the web or to the apparatus involved in placing and receiving the web roll. Moreover, the placement of the web rolls is very noisy disrupting the activities of personnel engaged in the web handling operations.
When doffing an empty roll core, after completion of the unwinding of a web roll, the belt of a belt let-off may be pulled as by moving one of the cradle support rolls outwardly and downwardly causing the empty roll core to roll off the belt. When in this position a full web roll is rolled upon the belt causing the belt to be snapped into its cradle configuration because at this point in the operating sequence of the let-off minimal support for the web roll is offered by the belt until it is pulled taught in its cradle configuration for supporting the web roll during unwinding.
It would conserve time and simplify the operation of the belt let-off if, instead of creating a problem, such positioning of the belt for discharging the empty roll core could thereafter be utilized to facilitate the placement of a full roll core as well as to cushion the impact thereof as it is rolled into operating position on the belt.